At present, most broadband mobile communication adopts distributed base station architecture, that is, Building Base band Unit (BBU) and Radio Remote Unit (RRU) are connected by optical fibre. However, the RRU is generally installed at top end of an antenna tower where the work environment is harsh and heat is dissipated by the passive cooling. Further, since the RRU is exposed to the outdoor environment, the machine shell is needed to be hermetical.
Therefore, when atmosphere temperature is high, especially at summer noon, the heat dissipation capacity of the RRU is subjected to a serious challenge. Performance and service life of critical components inside the RRU, such as power amplifier, power supply and FPGA (Field-Programmable Gate Array) would be greatly influenced by the temperature. In worse conditions, this may cause the components in the RRU to be ineffective (for example, the power amplifier is burnt out, and thermal protective outage of the power supply module occurs (burnt out)), such that the base station where the RRU is installed could be out of service and network coverage may be influenced.
Thus, the RRU is provided with an over-temperature alarm, that is, a temperature threshold is set up. When the temperature in the shell monitored by a temperature sensor in the RRU is higher than the temperature threshold, an over-temperature alarm message may be reported to a main station. No further processing operations are adopted thereafter. Meanwhile, the monitored temperature may be updated every once in a while.
In the above method, however, although the over-temperature alarm is reported when the temperature in the shell exceeds the temperature threshold, the RRU will keep working without any other processing operations. The temperature in the shell where the RRU is located may increasingly rise up, which may finally cause that the power amplifier or the power supply module is burnt out and the base station is ineffective. Therefore, the above method still may not solve the problem resulted from that the temperature of the RRU is excessively high.